Sex was painful (but 100% consensual, loving and respectful...) for me the first few times. And to be honest, it can be painful even now, especially if I've had a dry spell. It's like the muscles tighten up again over time or something. So I've found that 'little and often' works best if I'm trying to stay loose. A lot of it is in my head - my partner doesn't feel as much of a difference between when I say it's tight and when I'm getting into it. So you have to communicate. I've actually just bought my first dildo, having been sexually active for 14 years! When daily sex is happening, that's when it feels best for me, with communication being key - starting slow etc.

Someone else here has left a great comment about relaxing, focusing on your pleasure (usually the clit) and not forcing it in, and definitely take that advice. Take your time, it'll happen! Also check out advice for avoiding getting vaginal yeast infections and urine infections, penetration hurts like hell if you've got either (or both) of those. Basically pee after sex - I assume after sex with a dildo, too - don't wear tight clothing on long walks, cotton underwear is better than polyester for breathability, don't overwash down there, and clean that dildo every single time, before and after.